Lesson 13 Make a Ten Using Decomposition (Worksheet)

Part 1: Review the Ten and another strategy from lesson 4 and 5. Since one of the addends in problem is a 10, notice how you do not have to count one by one to find the sum. Part 2: In the problem 9 + 4, we do not have a ten to help us. If you have not memorized this fact yet, do not start counting one by one on your fingers. Instead, use the Make a Ten strategy, and you will see the answer without having to count one by one.

• Step 1. Look at the problem 9 + 4. Notice that the top frame with 9 counters only needs one more counter to make a ten.
• Step 2. Cross out the last counter from the bottom frame and move it up into the empty space in the top frame. Now that you have made a ten, it’s easy to visualize the answer.

Part 3: Make a Ten in the top frame by crossing out the correct number of counters in the bottom frame and moving them up. If you have already memorized these facts, great work. Show the decomposition anyway so you know where the answers came from and so you know how to use decomposition later for bigger problems.